Final answer:
The annual temperature ranges of a lake is an abiotic factor within a Florida ecosystem, as it is a nonliving environmental condition. The other options are biotic factors because they involve living organisms.
Step-by-step explanation:
In a Florida ecosystem, an abiotic factor would be the nonliving elements that influence the environment. The options given include a mushroom in a corn field, a deer in a forest, insect species in a corn field, and annual temperature ranges of a lake. Out of these, the annual temperature ranges of a lake is an abiotic factor within a Florida ecosystem, as it pertains to nonliving environmental conditions that affect the ecosystem.